IFMAR legal, specially-designed 4WD front wheels with 12mm interior hex. Perfect fit, and perfect for high-competition competition. The tires are made of flexible product while nevertheless being durable against effects. Along side it of wheel is aerodynamic for maximum performance. Medium hardness. Special options that come with the wheel are visible through the inside: reinforcement ribs to make the tires as stable as you are able to and eradicate deformation. Set of 5 pairs (10 pcs) the price of 4 pairs. An incredible value pack. Fits all XB4